Multiple function of macrophage scavenger receptors mediated by fibrous coiled coil domains

Type I and type II macrophage scavenger receptors (MSR) have six structurally distinct domains. MSR are known to mediate a wide range of ligand recognition, endocytosis, phagocytosis and macrophage adhesion. Expression of mutated receptors in various cultured cells and analysis using synthetic peptides indicate that two coiled-coil domains, alpha-helical coiled-coil domain (domain IV) and collagen-like domain (domain V) mediate these functions. Domain IV is essential for the trimerization of MSR and EDTA-resistant adhesion function. Domain V is essential for the wide range of ligand recognition. Cooperation of these two domains is also essential for the cellular function of MSR including pH-dependent ligand dissociation.